Oncogenic KRAS mutations occur in approximately 30% of lung adenocarcinoma. Despite several decades of effort, oncogenic KRAS-driven lung cancer remains difficult to treat, and our understanding of the regulators of RAS signalling is incomplete. Here to uncover the impact of diverse KRAS-interacting proteins on lung cancer growth, we combined multiplexed somatic CRISPR/Cas9-based genome editing in genetically engineered mouse models with tumour barcoding and high-throughput barcode sequencing. Through a series of CRISPR/Cas9 screens in autochthonous lung cancer models, we show that HRAS and NRAS are suppressors of KRAS^G12D-driven tumour growth in vivo and confirm these effects in oncogenic KRAS-driven human lung cancer cell lines. Mechanistically, RAS paralogues interact with oncogenic KRAS, suppress KRAS–KRAS interactions, and reduce downstream ERK signalling. Furthermore, HRAS and NRAS mutations identified in oncogenic KRAS-driven human tumours partially abolished this effect. By comparing the tumour-suppressive effects of HRAS and NRAS in oncogenic KRAS- and oncogenic BRAF-driven lung cancer models, we confirm that RAS paralogues are specific suppressors of KRAS-driven lung cancer in vivo. Our study outlines a technological avenue to uncover positive and negative regulators of oncogenic KRAS-driven cancer in a multiplexed manner in vivo and highlights the role RAS paralogue imbalance in oncogenic KRAS-driven lung cancer.

大约 30% 的肺腺癌发生致癌KRAS突变。尽管经过数十年的努力，KRAS 驱动的致癌肺癌仍然难以治疗，而且我们对 RAS 信号传导调节因子的了解还不完整。为了揭示多种 KRAS 相互作用蛋白对肺癌生长的影响，我们将基因工程小鼠模型中基于 CRISPR/Cas9 的多重体细胞基因组编辑与肿瘤条形码和高通量条形码测序相结合。通过在本地肺癌模型中进行的一系列 CRISPR/Cas9 筛选，我们表明 HRAS 和 NRAS 是体内 KRAS ^G12D驱动的肿瘤生长的抑制剂，并在 KRAS 驱动的致癌人肺癌细胞系中证实了这些作用。从机制上讲，RAS 旁系同源物与致癌 KRAS 相互作用，抑制 KRAS-KRAS 相互作用，并减少下游 ERK 信号传导。此外，在 KRAS 驱动的致癌人类肿瘤中发现的HRAS和NRAS突变部分消除了这种效应。通过比较 HRAS 和 NRAS 在致癌 KRAS 和致癌 BRAF 驱动的肺癌模型中的肿瘤抑制作用，我们证实 RAS 旁系同源物是体内 KRAS 驱动的肺癌的特异性抑制剂。我们的研究概述了一种在体内以多重方式发现致癌 KRAS 驱动的癌症的正负调节因子的技术途径，并强调了 RAS 旁系同源物失衡在致癌 KRAS 驱动的肺癌中的作用。